股骨颈骨折garden分型英文版

The Thai Journal of Orthopaedic Surgery Vol.27 No.1 March 2002 Observer Variation in Garden’s Classification of Femoral Neck Fractures Prakasit Sanguanjitra, M.D., Banchong Mahaisavariya, M.D. Department of Orthopedic Surgery and Rehabilitation Faculty of Medicine Siriraj Hospital Mahidol University, Bangkok 10700 ABSTRACT Intra- and inter-observer variation in the use of Garden’ classification of femoral neck fractures was evaluated. Pre-operative radiographs of 90 patients were assessed independently by 10 observers. Each observer evaluated and classified each radiaograph three times with at least 2 weeks interval between each time of assessment. The results showed poor agreement among observers. Median Kappa coefficient of intra-observer variation was 0.32 and inter-observer variation was 0.35, 0.26 and 0.38 in orderly. When the classification was modified into nondisplaced and displaced, the level of agreement was acceptable. INTRODUCTION Femoral neck fractures are most commonly classified according to Garden’s classification. This classification is based on assessment of the antero-posterior radiograph only. 1 Because this classification is intended to provide therapeutic guideline and enable comparison between different treatment methods. It is therefore important that the classification is reliable. Although there are some previous reports concerning the reliability of this classification, 2,3 there is no any study has been conducted in our real practice in Thailand. We therefore conducted this reliabilty study to assess the level of agreement or its variations among both inter- and intra-observers. MATERIAL AND METHOD A total of 90 cases of femoral neck fractures treated in our department during 1998 to 2000 were included in this study. The antero-posterior (AP) radiographs of both hip joints of the patients were used for the assessment and classified according to Garden’s classification (Fig. 1). There were 67 females and 23 males whose ages ranged from 18-95 years with an average of 70.1 years. There were 10 observers ( 5 from 3rd year residents and 5 from 4th year residents) who participated in this study. The method and details of Garden’s classification of femoral neck fractures were explained to all observers prior to start the study. The series of radiographs was studied by each observer working alone. Each observer were asked to assess the Garden’s stage according to the description made in 19611 (Fig. 2): The Thai Journal of Orthopaedic Surgery Vol.27 No.1 March 2002 Stage I: Incomplete fracture (impact valgus fracture) Stage II: Complete fracture without displacement Stage III: Complete fracture with partial displacement Stage IV: Complete fracture with full displacement Each observer were asked to assess the series of radiograph for 3 times with at least 2 weeks duration of interval between each time of asssessment. Statistics To assess the reliability of this study we a coefficient of agreement corrected for chance a es between +1 and a negative worst possible value> is +1; Kappa = 0 when the observed agreement Po is Pe . Kappa values greater than 0.75 are defined as e 0.50 as poor agreement.3 RESULTS Median Kappa coefficient of intraobserver coefficient among observers of first, second and th and 0.38 respectively. When the conditions were categorized as and displaced fractures (Garden’s stage III & IV) with median Kappa coefficient was 0.61. The med for each time of assessment were 0.59, 0.46 and 0.6 Fig.1 The antero-posterior radiograph of both hip joints was used for the study of observer variation of Garden’s classification. Fig.2 Four stages of femoral neck fractures according to Garden’s classification. used the Kappa statistics. Kappa is greement. Kappa can assume valu /= -1. For perfect agreement Kappa equal to expected chance agreement xcellent agreement and values below was 0.32 (0.24-0.44). Median Kappa ird time of assessment were 0.35, 0.26 nondisplaced (Garden’s stage I & II) the intra-observer agreement is higher ian Kappa coefficient of intra-observer 4 respectively (Table I). The Thai Journal of Orthopaedic Surgery Vol.27 No.1 March 2002 Table I Overall inter- and intra-observer variations from 10 observers in assessment of 90 cases of femoral neck fractures using Garden’s classification and modified Garden’s classification. Kappa coefficient Garden Modified Garden Intra-observer 0.32 0.61 Inter-observer 1st reading 0.35 0.59 2nd reading 0.26 0.46 3rd reading 0.38 0.64 DISCUSSION Garden’s classification of femoral neck fractures seemingly consists of four well defined stages.1 The classification serves as a guideline for treatment and it is therefore particulary important to determine the reliability of a classification system. From previous studies concerning the observer variation in Garden’s classification, Frandsen et al2 found that among 8 observers who assessed radiographs of 100 cases of femoral neck fractures only 22 cases that all observers were identified identically. Thomsen et al reported the observer variation in using Garden’s classification among 6 observers in evaluation of 96 cases of femoral neck fractures.3 It was found that the level of agreement was poor for overall classification with Kappa coefficient of 0.39. The author also found that when reducing Garden’s system into non-displaced (Stage I & II) and displaced fractures (Stage III & IV) the level of agreement became acceptable with Kappa coefficient of 0.68. From this study, we found a similarly poor agreement of the Garden’s classification of femoral neck fracture. The median Kappa coefficient of intra-observer among 10 observers was 0.32. We also experienced the same result that when reducing the Garden system to non-displaced and displaced femoral neck fractures we found better agreement with median Kappa coefficient of 0.61. This improvement was very similar to the result from the study of Thomsen et al.3 On the basis of our study, we conclude that Garden’s classification is poorly reproducible between observers. By reducing Garden’s system to the categories, non- displaced fractures (Stage I & II) and displaced fractures (Stage III & IV) the level of agreement become acceptable. This will make comparison between different studies more reliable. REFERENCES 1. Garden RS. Low angle fixation in fractures of the femoral neck. J Bone Joint Surg [Br] 1961; 43-B: 647-63. 2. Frandsen PA, Anderson E, Madson F, Skjodt T. garden’s classification of femoral neck fracture: an assessment of inter-observer variation. J Bone Joint Surg [Br] 1988; 70-B: 588-90. 3. Thomsen NOB, Jensen CM, Skovgaard N, Pedersen MS, Pallesen p, Soe-Nielsen NH, Rosenklint A. Observer variation in the radiographic classification of fractures of the neck of the femur using Garden’s system. Int Orthop 1996; 20: 326-9. Observer Variation in Garden’s Classification of Femoral Neck Fractures Faculty of Medicine Siriraj Hospital Mahidol University, Bangkok 10700 ABSTRACT INTRODUCTION MATERIAL AND METHOD Statistics RESULTS DISCUSSION REFERENCES